Electronic dice and method of determining dice number thereof

ABSTRACT

The present invention relates to an electronic dice and a method of determining a dice number. There is provided an electronic dice in which an acceleration sensor and a wired or wireless transmit-receive unit are provided. According to the electronic dice of the present invention, the dice number can be determined and transmitted to an external device based on changes in acceleration values over time, which are detected by the acceleration sensor in accordance with the movement of the dice, thereby combining play of the physical dice with a software game.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a technique of an electronicdice, and more specifically, to an electronic dice of a new type and amethod of determining a dice number thereof, in which an accelerationsensor and a transmit-receive unit are provided in a physical polyhedrondice, and the dice number is determined and transmitted to an externaldevice based on changes in acceleration values over time, which aredetected by the acceleration sensor in accordance with the movement ofthe dice, thereby combining play of the physical dice with a softwaregame.

2. Description of the Related Art

When a user plays a game using a dice conventionally, the user firstthrows the dice. Then, the user confirms a numeral or the number ofspots marked on the topmost face of the thrown dice with eyes as a dicenumber and applies the dice number to the game or play.

Recently, computers provide a random selection function on behalf of aphysical dice. However, since the amusement of throwing a real dice islimited in a dice game using a computer, it has been required to developa technique capable of combining the action of throwing a real dice witha software game executed in a computer.

An electronic dice has been proposed in order to meet the requirement,in which electronic devices are embedded in a conventional physicaldice, and a dice number obtained by throwing the dice is transmitted toan external electronic device such as a computer.

For example, the Korean Patent Laid-opened Publication No.10-2006-0000802 discloses an electronic dice provided with infraredsensors, light emitting devices and an electronic circuit unit inside aphysical dice having a cube shape. According to the conventionaltechnique, when the dice is thrown onto a certain bottom surface, theelectronic circuit unit provided inside the electronic dice identifies aface of the dice most closely contacted to the bottom surface,automatically determines a numeral or the number of spots on the topface of the dice, and wirelessly transmits a signal corresponding to thenumeral or the number of spots to an outside apparatus. However, theconventional technique has a problem in that since each of infraredsensors should be installed into each face of the cubic dice,respectively, the dice has inevitably a complex structure and consumesmuch power accordingly, and the infrared sensors may functionerroneously due to environmental conditions surrounding them.

In this respect, in the technical field pertinent to the presentinvention, there is a technical requirement for uniformly detecting avalue regardless of external environmental conditions while the sensorsand the circuit unit embedded in the electronic dice consume only lesspower. A sensor that can satisfy the requirement is known to be aninertial sensor capable of detecting the force of inertia from anacceleration applied to a moving object, or an acceleration sensorcapable of detecting the change of velocity per a unit time. Recently,these sensors are designed to be miniaturized and consume less power byapplying the Micro Electro Mechanical System (MEMS) technique anddeveloped as a multi-axis sensor, and thus the sensors have an optimumcondition to be applied to an electronic dice.

However, since the inertial and acceleration sensors are too sensitive,even a movement such as fine trembling of a hand can be sensed when auser holds an object with the hand, and the sensors malfunctionunexpectedly. An example of a technique for solving the problem by amethod of correcting errors using a software within a circuit isdisclosed in the Korean Patent Publication No. 10-0940095 of “a devicefor calculating a value of movement of a pointer, a method of correctinga value of movement of a pointer and a 3-dimensional pointing deviceusing the same”. According to the above technique, a value sensed by asensor detecting the slope of a pointer can be corrected using aspecific algorithm executed by a processor, and thus it is possible toprevent malfunctions caused by the accumulation of errors generated byunnecessarily sensing fine trembling of a hand.

However, the above conventional technique for correcting fine tremblingof a hand holding a pointer has difficulty in being applied when a diceheld in a hand is thrown. Accordingly, it is difficult to apply thetechnique to an electronic dice as it is, and a new algorithmappropriately applicable to the movement of a thrown dice is required.

As a result of continued studies on the technique, the inventor hasdeveloped an electronic dice comprising an acceleration sensor ofminiaturized low-power elements, which can detect the movement of thedice, determine a dice number based on the detection values and transmitthe dice number to an external device, and a new algorithm capable ofdetermining the dice number appropriately applicable to the movement ofthe electronic dice.

SUMMARY OF THE INVENTION

Accordingly, the present invention is conceived to solve the problems inthe prior art as described above. It is an object of the presentinvention to provide an electronic dice provided with an accelerationsensor therein for transmitting a dice number determined by a newalgorithm to an external device, and a method of determining the dicenumber.

Specifically, an object of the present invention is to provided anelectronic dice of a new type and a method of determining a dice numberthereof, in which an acceleration sensor and a wired or wirelesstransmit-receive unit are provided in a physical polyhedron dice, andthe dice number is determined and transmitted to an external devicebased on changes in acceleration values over time, which are detected bythe acceleration sensor in accordance with the movement of the dice,thereby combining play of the physical dice with a software game

The objects are accomplished by an electronic dice and a method ofdetermining a dice number according to the present invention.

According to an aspect of the present invention for achieving theobjects, there is provided an electronic dice comprising: a main bodyhaving a regular polyhedron shape; an acceleration sensor disposed at acenter of the main body to sense acceleration values with respect tothree perpendicular axes; a control unit for determining that theelectronic dice has moved from a stationary state if a displacement ofan acceleration value sensed by the acceleration sensor exceeds apredetermined threshold value for a certain period of time, determininga state as a peak detection state if the displacement of theacceleration value over time exceeds a predetermined thresholddisplacement, determining a state as a stationary state or a completedstate where the action of rolling the dice has been completed if thedisplacement of the acceleration value is smaller than the predeterminedthreshold value for a certain period of time, and determining a dicenumber based on the acceleration values sensed in the stationary stateor the completed state; and a transmit-receive unit for transmitting thedice number determined by the control unit to an external device.

The electronic dice according to an embodiment of the present inventionmay further comprise a memory unit for storing the acceleration valuessensed by the acceleration sensor and previously storing numerals of thedice each of which is allocated depending on whether a direction of atop face of the stationary dice is +X, −X, +Y, −Y, +Z or −Z. The controlunit can determine the direction of the top face of the stationary dicebased on the acceleration values sensed with respect to the three axesof X, Y and Z in the stationary or completed state, and determine thedice number by reading said numerals of the dice each of which isallocated depending on whether the direction of the top face of thestationary dice is +X, −X, +Y, −Y, +Z or −Z, from the memory unitstoring said numerals previously.

The electronic dice according to an embodiment of the present inventionmay further comprise an output unit for visually or aurally expressingan operation state of the electronic dice or the operation result for auser.

In the electronic dice according to an embodiment of the presentinvention, the acceleration sensor may have a measurement range of ±2 gfor each axis, and the predetermined threshold displacement for sensingthe peak detection state may be 1 g.

In the electronic dice according to an embodiment of the presentinvention, the transmit-receive unit is preferably an apparatus capableof communicating through a short-range wireless communication. Thetransmit-receive unit may be an apparatus capable of communicating withthe external device through a short-range wireless communication such asBluetooth, wireless USB, Zigbee, Infrared Data Association (IrDA),Nordic, SimliciTi or the like. The external device preferably includesall kinds of computing devices provided with a short-range wirelesscommunication means such as a personal computer (PC), a mobile Internetdevice (MID), a notebook, a netbook, a cellular phone, a smart phone, asmart TV, a conventional TV, an Internet Protocol television (IPTV), apersonal digital assistant (PDA) or the like.

In the electronic dice according to an embodiment of the presentinvention, the main body of the electronic dice may be a regulartetrahedron, a regular hexahedron, a regular octahedron, a regulardodecahedron, a tetradecahedron, or the like.

According to another aspect of the present invention, there is provideda method of determining a dice number of an electronic dice, the methodcomprising the steps of: determining that the electronic dice has movedfrom a stationary state if a displacement of an acceleration valuesensed by an acceleration sensor exceeds a predetermined threshold valuefor a certain period of time, the acceleration sensor being disposed ata center of a main body of the electronic dice having a regularpolyhedron shape, and sensing acceleration values with respect to threeperpendicular axes; determining a state as a peak detection state if thedisplacement of the acceleration value over time exceeds a predeterminedthreshold displacement; determining a state as a stationary state or acompleted state where the action of rolling the dice has been completedif the displacement of the acceleration value is smaller than thepredetermined threshold value for a certain period of time; anddetermining a dice number based on the acceleration values sensed in thestationary state or the completed state, and transmitting the dicenumber to an external device.

In the method of determining a dice number of an electronic diceaccording to an embodiment of the present invention, a direction of atop face of the stationary dice may be determined based on theacceleration values sensed with respect to the three axes of X, Y and Zin the stationary or completed state. The dice number may be determinedby reading numerals of the dice each of which is allocated depending onwhether the direction of the top face of the stationary dice is +X, −X,+Y, −Y, +Z or −Z, from a memory unit storing said numerals previously,and transmitted to the external device.

The method of determining a dice number of an electronic dice accordingto an embodiment of the present invention may further comprise visuallyor aurally expressing an operation state of the each step or theoperation result for a user.

In the method of determining a dice number of an electronic diceaccording to an embodiment of the present invention, the transmitting ofthe dice number to the external device may be performed through ashort-range wireless communication. For example, the short-rangewireless communication may be a short-range wireless communication usingBluetooth, wireless USB, Zigbee, Infrared Data Association (IrDA),Nordic, SimliciTi or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a schematic internal structure ofan electronic dice according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of an internalcircuit in an electronic dice according to an embodiment of the presentinvention.

FIG. 3 is a flowchart illustrating a method of determining a dice numberby detecting movements of an electronic dice according to an embodimentof the present invention.

FIG. 4 is a graph showing a relationship between changes in accelerationvalues over time and each detection step in the method of determining adice number by detecting movements of an electronic dice according to anembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, preferred embodiments according to the present inventionwill be described in detail with reference to the accompanying drawings.The following embodiments of the present invention are just to implementthe present invention and are not intended to limit or restrict thescope of the present invention. All techniques easily conceivable bythose skilled in the art from the detailed descriptions and embodimentsof the present invention are interpreted as belonging to the scope ofthe present invention. The references cited herein are incorporatedherein by reference.

An electronic dice according to an embodiment of the present inventionis directed to a physical dice easy to handle capable of beingconstructed using an acceleration sensor, particularly, using anacceleration sensor manufactured by the MEMS technique forminiaturization and less power consumption.

In addition, according to the present invention, a dice number can bedetermined based on the degree of changes of acceleration values onthree axes (i.e., the displacement of the acceleration value), in astate of holding a stationary dice with a hand and starting moving thedice, a state of dropping the thrown dice onto a bottom or bumping intoan object, and a state of stopping the dropped or bumped dice. The dicenumber determined as described above may be transmitted to an externaldevice, such as a personal computer (PC), a mobile Internet device(MID), a notebook, a netbook, a cellular phone, a smart phone, a smartTV, a conventional TV, an Internet Protocol television (IPTV), apersonal digital assistant (PDA) or the like, through a short-rangewireless communication. At this time, the external device may beexecuting a game software using the transmitted dice number.

Generally, games executed in a personal computer, a smart phone, a smartTV or the like can be interfaced with a user by various methods. Thereare various methods for interfacing games with a user. For the methods,a dice capable of generating diverse random numbers are frequently usedfor inducing user's interests in the games. Currently used computergames operate to adopt a virtual dice by implementing a dice software,and a number selected from the virtual dice is used as a variable of thegames. However, from the viewpoint of the user, a conventional method ofrolling a physical dice may be preferred.

Taking into consideration of the above viewpoint, the present inventionprovides a new interface between a game and a user using an electronicdice for transmitting a dice number to a game executed in a personalcomputer, a smart phone or a smart TV, the electronic dice being apolyhedron electronic dice for detecting a numeral of the dice using anacceleration sensor.

As shown in FIG. 1, an electronic dice 10 according to an embodiment ofthe present invention may comprise an acceleration sensor 17, a battery15 and a circuit board 13 inside a main body 11 having a cubic shape.The circuit board 13 is preferably configured as a printed circuitboard. The battery 15 intervenes between the top and the bottom boards13, which are disposed at the center of the main body 11 in order tomaintain the center of gravity of the electronic dice 10. Theacceleration sensor 17 is also placed at the center of the circuit board13 to measure acceleration values with respect to three axes.

As is shown in FIG. 2, the acceleration sensor 17 disposed at the centerof the circuit board 13 is connected to a control unit 131. The controlunit 131 is connected with the battery 15, a memory unit 133, atransmit-receive unit 135 and an output unit 137 to control theoperations of the acceleration sensor 17, the memory unit 133, thetransmit-receive unit 135 and the output unit 137.

Although the main body 11 is a cube in the example shown in FIG. 1, itis apparent that it is not limited only to a cube in the presentinvention. That is, a main body having any regular polyhedron shape maybe used in the present invention. For example, the main body 11 may beformed in a regular tetrahedron, a regular hexahedron, a regularoctahedron, a regular dodecahedron, a tetradecahedron, or the like.

The battery 15 supplies electric power for operating the accelerationsensor 17 and the components mounted on the circuit boards 13.

The acceleration sensor 17 is disposed at the center of the main body11, i.e., the center of gravity to sense acceleration values of threeperpendicular axes, i.e., axis X, axis Y, and axis Z. For example, athree-axis digital acceleration sensor manufactured by any knowntechnique in the art, e.g., the MEMS technique may be used as theacceleration sensor 17.

For example, an acceleration sensor of model No. CMA3000-D01(commercially available from VTI Technologies, Inc.) or an accelerationsensor of model No. ADXL345 (commercially available from Analog Devices,Inc.) may be used as the acceleration sensor 17. The acceleration sensorof model No. CMA3000-D01 may have a measurement range of ±2 g or ±8 g,and the acceleration sensor of model No. ADXL345 may have a measurementrange of ±2 g, ±4 g, ±8 g, or ±16 g.

In an embodiment of the present invention, an acceleration sensor havinga measurement range of about ±2 g for each axis can be used as theacceleration sensor 17. If the acceleration sensor having a measurementrange of ±2 g has a resolution of 10 bits, the resolution can beconverted into a resolution of 4 g/1024 using an ADC, and if theacceleration sensor has a resolution of 12 bits, the resolution can beconverted into a resolution of 4 g/4096 using an ADC. However, thepresent invention is not limited to the exemplary acceleration sensor asdescribed above, and it is apparent that a variety of accelerationsensors known in the art can be used.

In the example shown in FIG. 1, each of the circuit boards 13 isdisposed on the top and bottom of the battery 15, respectively todistribute their weights symmetrically and thus to distribute the wholeweight of the electronic dice 10 in circular symmetry with respect tothe acceleration sensor 17 disposed at the center of the electronic dice10.

The memory unit 133 stores data sensed by the acceleration sensor 17. Inaddition, the memory unit 133 may store various software commandsrequired to operate the control unit 131, and various reference datasuch as a threshold value for determining a transition from a stationarystate and/or a threshold displacement for determining a peak detectionstate.

The transmit-receive unit 135 is a communication means capable ofcommunicating with an external device through a wired communication or ashort-range wireless communication such as Bluetooth, wireless USB,Zigbee, Infrared Data Association (IrDA), Nordic, SimliciTi, or thelike. For example, a communication protocol of BT, Nordic, SimliciTi orthe like may be used as a communication protocol for the wirelesscommunication of the transmit-receive unit 135. Meanwhile, it isapparent that a short-range wireless communication device and/or acommunication protocol that can be used in the present invention is notlimited to the communication devices and protocols as described above,but those skilled in the art can adopt a variety of short-range wirelesscommunication devices and/or communication protocols used in the fieldof the present invention.

The output unit 137 may include, for example, a light emitting diode(LED), a vibrator, a buzzer, or the like, and thus may visually oraurally express the operation state of the dice 10 for a user.

The control unit 131 can determine a dice number in accordance with thealgorithm of the present invention with controlling the operations ofthe acceleration sensor 17, the memory unit 133, the transmit-receiveunit 135 and the output unit 137. The control unit 131 can detect themovement of the dice 10 and determine a dice number based onacceleration values with respect to each of three axes sensed by theacceleration sensor 17 and changes of the acceleration values over time(i.e., the displacement of the acceleration value).

The movement of the dice 10 detected by the control unit 131 may includefour different states such as a stationary state, a peak detectionstate, a stop detection state, and a completed state. The control unit131 determines that the dice 10 has been thrown only when the fourstates are consecutively detected to determine a dice number.

A method of determining a dice number by the electronic dice 10according to an embodiment of the present invention configured asdescribed above is shown in FIG. 3 as an example.

Referring to FIG. 3, if a user holds the electronic dice 10 with a handand throws the dice 10 on a bottom, the control unit 131 checksacceleration values sensed by the acceleration sensor 17 at certain timeintervals, e.g., nanoseconds or microseconds, and determines that thedice 10 is in a stationary state (or a sleep state) if the accelerationvalues do not exceed a predetermined threshold value, e.g., ⅙ g (S301).

The acceleration sensor 17 reads acceleration values of three axes of X,Y and Z under the control of the control unit 131 (S302). If adisplacement of the read acceleration value exceeds the threshold value(e.g., ⅙ g, approximately corresponding to 10 DAC), the control unit 131determines that the dice 10 has moved from a stationary state to amoving state (i.e., there is a movement) (“Yes” of S303). This may meana state in which a user holds the dice 10 with a hand and is about tothrow the dice 10, or a state right after a user has thrown the dice 10.On the contrary, if the displacement of the read acceleration value issmaller than the threshold value (“No” of S303), the control unit 131determines that the dice 10 is still in a sleep state, and theacceleration sensor 17 returns to the step of S302.

In the case of “Yes” in the step of S303, the acceleration sensor 17reads changes in acceleration values over time in three axes of X, Y andZ under the control of the control unit 131 (S304). If a displacement ofthe read acceleration value exceeds a predetermined thresholddisplacement (e.g., 1 g, approximately corresponding to 70 DAC), thecontrol unit 131 determines that the dice 10 is in a peak detectionstate (or a high frequency vibration detection state) (“Yes” of S305).This may mean a state in which a user throws the dice 10 and the dice 10falls onto a bottom or bumps into an object. On the contrary, if thedisplacement of the read acceleration value is smaller than thethreshold displacement (“No” of S305), the acceleration sensor 17returns to the step of S304 and continues to read changes inacceleration values over time in three axes of X, Y and Z under thecontrol of the control unit 131.

When detecting a peak (a high frequency vibration), the control unit 131controls the output unit 137 to express visually or aurally starting ofdetection for determining a state of the dice 10, i.e., a dice numberfor a user (S306). For example, the LED visually emits light, or thebuzzer generates a certain beep sound, and thus a user may recognizestarting of a dice game.

Subsequently, the acceleration sensor 17 continues to periodically readchanges in acceleration values over time in three axes of X, Y and Zunder the control of the control unit 131 (S307). If a displacement ofthe acceleration value is smaller than the threshold value for a certainperiod of time, the control unit 131 determines that the dice 10 is in astationary or a completed state (“Yes” of S308). If the displacement ofthe read acceleration value is not smaller than the threshold value(“No” of S308), the acceleration sensor 17 returns to the step of S307and continues to periodically read changes in acceleration values overtime in three axes of X, Y and Z.

In the case of “Yes” in the step of S308, the control unit 131determines that the action of rolling the dice 10 is completed and thuscontrols the output unit 137 to express visually or aurally thestationary or completed state where the movement of the dice 10 isstopped for a user (S309). Then, the control unit 131 determines a dicenumber (a numeral) based on the acceleration values sensed in thestationary or completed state and transmits the dice number to anexternal device through the transmit-receive unit 135 (S310).

For example, the memory unit 133 previously stores numerals of the diceeach of which is allocated depending on whether a direction of a topface of the stationary dice is +X, −X, +Y, −Y, +Z or −Z. The controlunit 131 can determine the direction of the top face of the stationarydice based on the acceleration values sensed with respect to the threeaxes of X, Y and Z in the stationary or completed state, and determinethe dice number by reading said numerals of the dice each of which isallocated depending on whether the direction of the top face of thestationary dice is +X, −X, +Y, −Y, +Z or −Z, from the memory unit 133storing said numerals previously.

FIG. 4 is a graph showing a relationship between changes in accelerationvalues over time and each detection step in the method of determining adice number by detecting movements of an electronic dice according to anembodiment of the present invention. In the graph of FIG. 4,acceleration values detected with respect to each of three axes of X, Yand Z are expressed as curves of different colors, respectively. In theexample of FIG. 4, the horizontal axis is a time axis where a unit timehaving a time length of about 1/30 second is represented from 1 to 246.In addition, the vertical axis represents acceleration values in a rangeof ±150 digital acceleration (DAC) where 10 DAC corresponds toapproximately ⅙ g. In this case, the acceleration values are convertedinto DAC values, assuming that the acceleration sensor has a measurementrange of ±2 g and a resolution of 8 bits. In the detailed description ofthe specification, “g” denotes an acceleration of gravity.

Reviewing changes in acceleration values over time as shown in FIG. 4,it is seen that there are four separate dice states along the time axis.

The first state is a stationary (sleep) state (see a unit time [1:15]),and it is understood that there is no substantial change in accelerationvalues of the three-axis acceleration sensor. This is a state before themovement of the dice is detected. The transition from a stationary stateto a moving state (i.e., there is a movement) can be determined based onthe threshold value stored in the memory unit 133. The control unit 131controls the memory unit 133 to maintain an average of the accelerationvalues sensed by the acceleration sensor 17 in the memory unit 133. Thecontrol unit 131 controls the acceleration sensor 17 to periodicallycheck the acceleration values sensed by the acceleration sensor 17. If adisplacement of the average acceleration value exceeds the thresholdvalue (e.g., 10-DAC, approximately corresponding to ⅙ g) and thedisplacement of the average acceleration value exceeding the thresholdvalue is maintained for a certain period of time (e.g., 1 second), itmay be determined that there is a movement and the dice has moved from astationary state.

The second state is a peak detection state (see a unit time [16:156]).The peak detection state includes a transition state from the stationarystate where a displacement of an acceleration value of the three-axisacceleration sensor exceeds the threshold value. In the peak detectionstate, a high frequency component (i.e., a phenomenon that adisplacement of an acceleration value over time abruptly increases) canbe detected as shown in FIG. 4 (see a unit time [136:156]). If the dicefalls onto a bottom or bumps into an object, the acceleration valueabruptly changes, and thus the high frequency component is occurred as afrequency component of tens of Hz (e.g., 10 to 30 Hz) or more with itsamplitude of 1 g or more (corresponding to approximately 70 DAC). In thepresent invention, a high-pass filter may be additionally provided onthe circuit board 13 of the electronic dice 10 or embedded in theacceleration sensor as one chip, and a cut-off frequency of thehigh-pass filter may be set to the aforesaid high frequency.Accordingly, if the amplitude of the frequency component occurred anddetected as described above is more than the threshold displacement(e.g., 1 g) stored in the memory unit 133, the control unit 131determines this phenomenon as a peak detection. After a peak isdetected, the control unit 131 controls the dice to progress toward astop detection state, considering a phenomenon that the dice stopsspontaneously after the peak detection.

The third state is a stop detection state (see a unit time [156:171]).In this state, the acceleration sensor 17 determines whether all thedisplacements of the acceleration values sensed by the three-axisacceleration sensor drop below the threshold value (e.g., 10-DAC), underthe control of the control unit 131. If all the displacements ofacceleration values of the three axes detected by the accelerationsensor 17 are smaller than the threshold value, the control unit 131controls the dice to progress toward a completed state, considering aphenomenon that the dice stops slowly and gradually even after the stopdetection.

The fourth state is a completed state (see a unit time [171:246]). Inthis state, the acceleration sensor 17 detects whether the displacementof the acceleration value dropped less than the threshold value ismaintained for a certain period of time (e.g., 3 seconds), under thecontrol of the control unit 131. If the control unit 131 determines thatthe dice is in a completed state based on the detection of theacceleration sensor 17, it searches for an axis showing a certainacceleration value, for example, ±1 g among the three-axis accelerationvalues of the acceleration sensor 17. In the example of FIG. 4, sincethe acceleration value of axis X is −1 g (corresponding to approximately−48 DAC) in the completed state, the control unit 131 can determine thatthe top face of the dice is on axis +X thus and a numeral thereof is“3”. Accordingly, the control unit 131 can inform the external device ofthe result of the determination, i.e, “3”.

In this regard, the memory unit 133 previously stores numerals of thedice each of which is allocated depending on whether a direction of atop face of the stationary dice is +X, −X, +Y, −Y, +Z or −Z.Accordingly, the control unit 131 can determine a dice number, accordingto the axis direction and/or the corresponding direction of the top faceof the stationary dice, based on the data of the memory unit 133 and theacceleration values of the acceleration sensor 17.

For example, the memory unit 133 may store numerals of the top face ofthe stationary dice in accordance with each of axis directionscorresponding to three-axis acceleration values of the accelerationsensor 17 (See an example as below).

Example

Dice numeral 1: axis direction→−Z, in this case, the acceleration valueof the acceleration sensor of axis Z is −1 g;

Dice numeral 6: axis direction→+Z, in this case, the acceleration valueof the acceleration sensor of axis Z is +1 g;

Dice numeral 3: axis direction→−X, in this case, the acceleration valueof the acceleration sensor of axis X is −1 g;

Dice numeral 4: axis direction→+X, in this case, the acceleration valueof the acceleration sensor of axis X is +1 g;

Dice numeral 2: axis direction→+Y, in this case, the acceleration valueof the acceleration sensor of axis Y is +1 g; and

Dice numeral 5: axis direction→−Y, in this case, the acceleration valueof the acceleration sensor of axis Y is −1 g.

Accordingly, the control unit 131 can determine a dice number, accordingto the axis direction and/or the corresponding direction of the top faceof the stationary dice, based on the aforesaid data of the memory unit133 and the acceleration values of the acceleration sensor 17.

Meanwhile, although acceleration sensor values with respect to threeaxes in the completed state and a numeral on the topmost face of thedice stopped after being thrown may be determined in the method asdescribed above, this is only an example, and a dice number of thetopmost face of the dice may be determined in a variety of methods basedon acceleration values sensed in the completed state.

The present invention as described above in which an acceleration sensorand a wired or wireless transmit-receive unit are provided has theeffect that a dice number can be determined and transmitted to anexternal device based on changes in acceleration values over time, whichare detected by the acceleration sensor in accordance with the movementof the dice, thereby combining play of the physical dice with a softwaregame.

Although preferred embodiments of the present invention have beendescribed, the present invention is not limited thereto. It will beapparent that those skilled in the art can make various modificationsand changes thereto without departing from the spirit and scope of thepresent invention and the modifications and changes are also included inthe scope of the present invention.

1. An electronic dice, comprising: a main body having a regularpolyhedron shape; an acceleration sensor disposed at a center of themain body to sense acceleration values with respect to threeperpendicular axes; a control unit for determining that the electronicdice has moved from a stationary state if a displacement of anacceleration value sensed by the acceleration sensor exceeds apredetermined threshold value for a certain period of time, determininga state as a peak detection state if the displacement of theacceleration value over time exceeds a predetermined thresholddisplacement, determining a state as a stationary state or a completedstate where the action of rolling the dice has been completed if thedisplacement of the acceleration value is smaller than the predeterminedthreshold value for a certain period of time, and determining a dicenumber based on the acceleration values sensed in the stationary stateor the completed state; and a transmit-receive unit for transmitting thedice number determined by the control unit to an external device.
 2. Thedice as claimed in claim 1, further comprising a memory unit for storingthe acceleration values sensed by the acceleration sensor and previouslystoring numerals of the dice each of which is allocated depending onwhether a direction of a top face of the stationary dice is +X, −X, +Y,−Y, +Z or −Z.
 3. The dice as claimed in claim 2, wherein the controlunit determines the direction of the top face of the stationary dicebased on the acceleration values sensed with respect to the three axesof X, Y and Z in the stationary or completed state, and determines thedice number by reading said numerals of the dice each of which isallocated depending on whether the direction of the top face of thestationary dice is +X, −X, +Y, −Y, +Z or −Z, from the memory unitstoring said numerals previously.
 4. The dice as claimed in claim 1,further comprising an output unit for visually or aurally expressing anoperation state of the electronic dice or the operation result for auser.
 5. The dice as claimed in claim 1, wherein the acceleration sensorhas a measurement range of ±2 g for each axis, and the predeterminedthreshold displacement for sensing the peak detection state is 1 g. 6.The dice as claimed in claim 1, wherein the transmit-receive unit is anapparatus capable of communicating with the external device through ashort-range wireless communication using Bluetooth, wireless USB,Zigbee, Infrared Data Association (IrDA), Nordic, or SimliciTi.
 7. Amethod of determining a dice number of an electronic dice, comprising:determining that the electronic dice has moved from a stationary stateif a displacement of an acceleration value sensed by an accelerationsensor exceeds a predetermined threshold value for a certain period oftime, the acceleration sensor being disposed at a center of a main bodyof the electronic dice having a regular polyhedron shape, and sensingacceleration values with respect to three perpendicular axes;determining a state as a peak detection state if the displacement of theacceleration value over time exceeds a predetermined thresholddisplacement; determining a state as a stationary state or a completedstate where the action of rolling the dice has been completed if thedisplacement of the acceleration value is smaller than the predeterminedthreshold value for a certain period of time; and determining a dicenumber based on the acceleration values sensed in the stationary stateor the completed state, and transmitting the dice number to an externaldevice.
 8. The method as claimed in claim 7, wherein a direction of atop face of the stationary dice is determined based on the accelerationvalues sensed with respect to the three axes of X, Y and Z in thestationary or completed state, and the dice number is determined byreading numerals of the dice each of which is allocated depending onwhether the direction of the top face of the stationary dice is +X, −X,+Y, −Y, +Z or −Z, from a memory unit storing said numerals previously,and transmitted to the external device.
 9. The method as claimed inclaim 7, further comprising visually or aurally expressing an operationstate of the each step or the operation result for a user.
 10. Themethod as claimed in claim 7, wherein the acceleration sensor has ameasurement range of ±2 g for each axis, and the predetermined thresholddisplacement for sensing the peak detection state is 1 g.
 11. The methodas claimed in claim 7, wherein the transmitting of the dice number tothe external device is performed through a short-range wirelesscommunication using Bluetooth, wireless USB, Zigbee, Infrared DataAssociation (IrDA), Nordic, or SimliciTi.